316 EOCENE PERIOD. [Ch. XXII. 



extremity of the Isle of Wight, part of the fresh-water series 

 is vertical, like the marine. Hence it is now ascertained that 

 as the chalk is horizontal at the southern extremity of the Isle 

 of Wight, while it is vertical in the centre of that island, so the 

 Eocene strata are horizontal in the north of the island, and 

 vertical in the centre. We have only to imagine that the great 

 flexure of the secondary and tertiary beds, so ingeniously 

 suggested by Mr. Webster in his theoretical section *, extended 

 to the fresh -water formations, in order to comprehend how a 

 very simple scries of movements may have brought the whole 

 of the Isle of Wight groups into their present position. 



We are unable to assign a precise date to the convulsions 

 which produced this great curve in the stratified rocks of the 

 Isle of Wight ; but we may observe that, although subsequent 

 to the deposition of the fresh-water beds, it does not follow that 

 it was not produced in the Eocene period. It may have been 

 contemporaneous with those movements which raised the cen- 

 tral parts of the London and Hampshire basins, which, as we 

 before explained, were subsequent to the principal elevation and 

 denudation of the central axis of the Weald. 



Land has certainly been elevated on our eastern coast since 

 the commencement of the older Pliocene period, as is attested 

 by the moderate height attained by the crag strata-)-. But these 

 changes of level may have been partial, and if the crag does not 

 extend farther over the Eocene formations, and into the Weald 

 Valley, it is probably because those regions were dry land 

 when the strata of crag were forming in the sea. 



The first land that rose in the south-eastern extremity of 

 England may have been placed, as we before hinted, where we 

 now find the central axis of elevation in the Weald. Perhaps 

 the chalk islands there formed may have supported that 

 tropical vegetation whereof we find memorials in the fossil 



* Knglefield's Isle of Wight, plate XLVII. %. 1. 



f We alluded, at p. 182, to the supposed discovery of recent marine shells at 

 the height of 140 feet above the sea in Sheppey ; hut we have since learnt from 

 Professor Scdgwickj that the information communicated to the Geological Society 

 on this subject was erroneous. 



